A Private Universe

Convergencia de Medios, Tecnologías y Aprendizaje Universidad Nacional de Colombia Profesor: Fernando Díaz del Castillo Semana 2: Septiembre 2007 Guíon: A Private Universe

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Harvard Commencement Ideas That Block Learning Narrator: Despite a lifetime of the very best education, students in our classrooms are failing to learn science. Many of these students will graduate from college with the same scientific misconceptions that they had on entering grade school. To test how a lifetime of education affects our understanding of science we asked these graduates some simple questions in Astronomy. Consider for example that the causes of the seasons is a topic taught in every standard curriculum. Graduate 1: O.K. I think the seasons happen because as the Earth travels around the Sun, it gets nearer to the Sun, which produces warmer weather and gets farther away which produces colder weather. And thus the seasons. Graduate 2: How cold it is or how warm it is in any given time of the year has to do with the closeness of the Earth to the Sun during the seasonal periods. Graduate 3: The Earth travels around the Sun, and it gets hotter when are closer to the Sun, and it gets colder when we are farther away. Narrator: These graduates, like many of us, think of the Earth’s orbit as a highly exaggerated ellipse, even thought the Earth’s orbit is very nearly circular, with distance producing virtually no effect on the seasons. We carry with us the strong, incorrect belief that changing distance is responsible for the seasons. Graduate 1: I took physics, planetary motion, and relativity, and electromagnetism and waves. Graduate 2: I don’t really have a scientific background whatsoever, and I got through school without having it. I’ve gotter very far without having it. Graduate 3: I had quite a bit of science in high school, yeah. Through physics 1, first year, and two years of chemistry. Narrator: Regardless of their science education, 21 of the 23 randomly selected students, faculty and alumni of Harvard University revealed misconceptions when asked to explain either the seasons or the faces of the Moon. 1

Guión transcrito por Fernando Díaz del Castillo

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Graduate 4: When it’s further away from the Sun it gets colder. Professor 1: The Earth’s position interferes with the reflection of the Sun against the Moon. Narrator: To test how standard instruction succeeds or fails in reversing such misconceptions, we interviewed ninth grade students from a nearby high school. The students selected had little training in Astronomy. Student 1: Winter is when the Sun is farthest away from the Earth and when it’s… summer is when the Sun is closer to the Earth. Interviewer: Why is it hotter in the summer? Student 2: It’s hotter in the summer because we’re closer to the Sun than we are in the winter. Interviewer: Tell me about the different shapes of the Moon. Student 3: Of the Moon? When the Sun’s right here, the Earth blocks the sunrays and it causes the Moon to have a shadow right here… Narrator: That the monthly cycle of lunar phases is caused by the shadow of the Earth is another popular misconception. Interviewer: Can you tell me about the difference in seasons? What’s different about the seasons of the year. Student 4: In the summer time it’s like we’re closer to the Sun and the sun’s rays coming down, so it’s hot. And we move further away I guess it gets colder. Narrator: Unlike the Harvard graduates, theses students have had virtually no instruction in science. Interviewer: And does the Moon have different shapes? Student 2: No, it’s round. Interviewer: Does it ever look different than round? Student 2: Yeah, it does. It looks like a half-croissant. Kind’a looks like a half… Interviewer: And what causes that? Student 2: Uhm… clouds… blocking it. Let’s say we had a half . This is here with clouds and all you see is that. Narrator: Like a scientist in search of an explanation this student created his own unique theory to explain the phases. Teacher: I don’t know. You get some kind of key in a room as to why kids don’t 2

understand. Interviewer: If we went outside today, out in the grass, and we see the sun… what would things look like at say 8 o’clock. Heather: 8 O’clock… is uhmm… well the Sun would have ro… well the Earth would have rotated so that the Sun would be on the other side of the Earth so it would be dark here and we’d be able to see the start with the… yeah. Interviewer: Where would the stars be in the daytime? Heather: They’re still up there. We just can’t see them. It’s not dark enough. Teacher: Heather… Heather is very bright. On a scale of 1 to 10 I would probably put her on a 9… a little bit above the level of the other kids. And I would expect her to know the answers to these things. Heather: That’s the Sun. It’s a lot bigger. And there’s a plant and another planet and then there’s the Earth ‘cause it’s the third planet up from the Sun. And then there are six more planets.. and then… well the Earth revolves around the Sun and the Moon revolves around the Earth. So this goes like this and that goes like that. And each time the Earth goes like this is a day. And it takes 365 days for the Earth to go around the Sun and that’s a year. Narrator: You may recognize Heather as typical of your best student. Teacher: Yeah, I would expect that she could give a better explanation that the other kids. I think she’s a little bit… she a lot more sure of herself. The other kids I think might have been a little more inhibited and more afraid. I hope she’ll tell you what she knows. Heather: But the Earth doesn’t quite go in a circle. It’s more of… let’s see… it’s more like… that. Narrator: On probing we see that Heather believes that the Earth travels in a bizarre curlicue orbit. Heather: … and when it’s farther away it’s summer, and when it’s closer right here is winter. O. K. it’s winter when it’s closer and it’s summer when it’s farther away because of… uhm… at least for us it is. It’s when… because its axis. The sun’s rays are indirect it’s summer, ‘cause we get warmer. When the Earth is closer the sun’s beams are direct it’s colder. Interviewer: Can you draw a picture of what it means to be direct or indirect? Heather: O.K. when the light comes from the Sun, when it’s direct it comes straight from the Sun to the Earth. And when the light’s indirect it sort of bounces off and then comes to the Northern Hemisphere. It’s different. Narrator: Heather believes that light can bounce and that this somehow causes the 3

seasons. Heather: When it bounces off and then comes… I mean… it… well… it doesn’t go in a straight line, I guess. It’s more… it’s confusing. Inteviewer: What about the Moon… Teacher: This is… mind-bothering, you know? Heather: The Moon has like four cycles and sometimes it’s full, sometimes you can only see part of it, sometimes you just can’t see it at all, sometimes you can only see this part… sometimes it looks like a circle. Interviewer: Can you draw me a picture of how that happens? Heather: Well this is us over here and we can see the Moon. So the rays of the Sun come around and they only illuminate the part of the Moon, because I guess it’s the Earth’s shadow or something. Narrator: Heather’s private theories contradict the teachings of even the most elementary science courses. Teacher: You assume that they know certain things. Even the day I taught it I came in and assumed they had the basic ideas and they don’t. Narrator: Heather’s teacher was unaware of the students’ private theories as she taught them their first formal lesson in Astronomy.

[Lesson on the phases of the moon: not transcribed] Narrator: We interviewed Heather again two weeks after the lesson to see how her private theories were modified by teaching. Heather: What I got confused about was… uhm… if the Sun was here, what does the path look like, you know, that the Earth takes. And I wasn’t sure whether it went like this… or… but then we figured out that it sort of went like that. Teacher: I’m surprised that she remembered the exact picture she had drawn. I mean she didn’t even hesitate. It was like… right… like this. And when we started originally it sounded like such a crazy thing. I mean that really was her idea. It wasn’t just like maybe it’ll be like this, that really was her idea. Interviewer: What about this curlicue, where did you get that idea … Heather: I have no idea… it was probably because I was looking at my Earth Science book and looked at another chart and got it confused with this one.

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Narrator: In class Heather was able to reverse the misconception she had pieced together on her own from books and other sources. Heather: So… this one’s wrong! Narrator: But just as often misconceptions can originate in a classroom. For example the notion that the seasons are caused by the highly elliptical orbit of the Earth is a misconception which result from perspective drawings found in many textbooks. Let’s see how instruction has altered Heather’s other theories such as the one she holds about the phases of the Moon. Heather: There’s the Earth and the Moon is going around it in circles, so as the Moon goes around the Earth, at different points sometimes and the Sun illuminates different parts of the Moon. And as it goes around, people on Earth can see different phases of the Moon. The full Moon, the crescent Moon, the new Moon. Narrator: Heather appears able to recreate the teachers explanation perfectly. Interviewer: And what did you learn in class and what did you learn in… Heather: Here… in the other… in eighth grade class when you did the video tape? Uhm… well we learned the phases of the Moon, but we didn’t learn where the Moon was at those times. ‘Cause I don’t remember learning that. And that makes it sort of hard, ‘cause you know what the phases are, but you don’t know where the Moon was. I mean the Moon could be over here, could be over here, could be over here, could be… you know practically anywhere on its orbit around… Narrator: But she still has some lingering doubts. And when pressed shows that she still holds on to her private theory about the shadow of the Earth. Heather: I´m almost sure that a lunar eclipse is when the shadow of the Earth blocks the Moon and we can’t see it. But I’m not sure about the new Moon and the full Moon. Whether it’s that the, uhm, whether it’s that the… it’s because the Moon is in front of the Sun so that the back is getting the light and we can’t see the light or because it’s over here and over here’s the new Moon because of the shadow. But I think it’s over here it’s the full Moon. Yeah, that would make sense because… yeah I think over here’s the new Moon, and over here… no… over here’s the full Moon and over here’s the new Moon. Almost positive about that… almost, ha ha. Interviewer: When did you come to understand that? Heather: Well… if, if this was the new Moon, then a lunar eclipse wouldn’t be so special because the shadow will always, you know once a month would be shutting out the light of the Moon or the light that bounces off of the Moon. Uhm… so, as it… so then a lunar eclipse wouldn’t be so special… it wouldn’t be a big thing, it would just a lunar… you know… be called the new Moon. Narrator: If Heather hadn’t been forced to confront her private theory she might never have learned the correct explanation. 5

Teacher: But I also know that what happened was that she had to hold the things in her hands. I mean, you didn’t even or whoever was filming didn’t say “use this to show it”. How did that happen? And she immediately took them and started working with them and figuring it out. And I think too often that doesn’t happen with kids, that they don’t get to see it exactly in their hands and feel it. Narrator: We then asked Heather about the seasons and her theory of bouncing lights. Heather: The Earth is tilted and the Sun is right here. This would be… this is the Northern Hemisphere, so we would be having… summer. Like that. ‘Cause rays would go like that. And down here the would have winter and on the equator it would be summer all year long because they get pretty much straight rays. But when it’s over here, because this part of the Earth is showing toward the Sun that gets the direct rays and it means you’re having summer down here and winter up here. Narrator: Again Heather gave a perfectly acceptable explanation for the seasons. But then we asked her to define the terms Direct and Indirect. Heather: Direct rays are rays coming directly from the Sun. Indirect rays are when they come from the Sun and bounce off another object. Narrator: She does not let go of her theory of bouncing light. Heather: Sort if you had a light in front of a mirror. If you had a light bulb here, a mirror here and you twisted the lightbulb so it went like that, the light would bounce off the mirror to somewhere else… and… so if you had the mirror here and light here, then the light would bounce. […] and here we would have winter because it sort of bounces or something. Teacher: I don’t know where she picked that up, but somewhere along the line she did and she just doesn’t wanna let go of it. Narrator: Since Heather’s misconceptions were not directly addressed in the class lesson, we tried to alter her inappropriate definition of direct and indirect light through one-on-one instruction. Notice how she tries to blend these new concepts into her old. Heather: The Earth’s here and the Sun’s rays are going directly to the Northern Hemisphere. That would be summer. Because you know the rays are stronger. Both because the weren’t interrupted with anything and because they would be closer together. Like shown right here. And when the Northern Hemisphere is farther away it would be winter up here because the, uhm, from the Sun would have a slant and sort of bounce off other parts of the Earth. Narrator: Her own theory is so deeply ingrained that despite our attempts, she never abandons it. Teacher: I guess you have to realize that kids really do have the ideas coming in, and 6

you think that it’s like a void, but it’s not, they have experiences and they have ideas that they associate with other things. And until you kinda have straightened out those kinds of ideas, it kinda closes off their minds to what it is you’re trying to get across to them really. Narrator: Every time we communicate, new concepts compete with the preconceived ideas of our listeners. All students hold these ideas but are unaware of their private theories. We must make them aware. Only then can we enable them to learn and free them from this private universe. Referencias

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